First there's the buttery smoothness of the Kobe-style Wagyu beef from the Texas T producers, cut into shreds and molded into a cylinder, raw and pristine. Then the nuttiness of sesame oil kicks in, amplified by the toasted pine nuts native to Korea.

A faint red pepper heat wells up, and sea-salt crystals perched on the cylinder's rim answer. Their brisk crunch counters the richness of the yolk from the speckled quail egg on top, meant to be mixed in with chopsticks.

Finally, the soft orange blob of sea urchin - a grace note on top of the beef - adds its oceanic tang, underscored by dark-green seaweed squiggles racing across the plate. It's a brilliant mesh of land and sea, Korean flavors and classic technique, escorted by earthy taro chips as thin as vellum.

If only everything at Nara worked so well, the contemporary Korean-Japanese fusion restaurant would be one of the best in the city. Instead, it is a glamorous conundrum: beautiful, pricey and uneven, its soaring moments undercut by too many that are earthbound, derivative or simply puzzling.

The menu format takes some getting used to. Forget about the appetizer/entree progression and follow your server's advice about ordering as if you were eating "Korean tapas." Expensive Korean tapas, in many cases.

The successful dishes make me thrilled to be sitting in this svelte setting of pewters and charcoal grays, with perforated screens and lacelike window traceries making the room feel almost weightless. The sense of occasion makes the prices more bearable.

Yes, the slate of steamed buns is right from the Chang/Momofuku playbook (as is the order-ahead Bo Ssam). But each of the three buns I tried was fun to eat, from the Korean-style prime rib sliced thin and livened with pickled red onion and carrot, to a seared peppercorn-tuna version. An unusual caramelized chicken-meatball bun, cradled by soft petals of bibb lettuce and sweet glazed onions, was all grace and freshness.

A rarefied seafood take on bibimbap, the homey Korean rice bowl, may stun with its $19 price tag and its diminutive size. But wow, is it fun to pick apart with chopsticks, savoring a satiny Japanese diver scallop here and a hunk of king crab there, with slivers of raw yellowfin tuna adding cool, smooth tones. A tall bonnet of quail egg and daikon radish sprouts add drama.

Even a specialty sushi roll can overcome my jaundiced view of the species, which I think of as sushi for people who don't really like fish. The Crunchy Yellowtail Roll is simple enough to highlight the clean flavor of hamachi, the Japanese amberjack. Miso-spiked guacamole and clever tempura-fried cilantro leaves ride on top of the rice package, adding texture and snap without overwhelming.

Sushi rolls are one of the ways chef Chang made his name at Uptown Sushi, his successful and clubby spot north of the Galleria in the ritzy Uptown Park mall. He's held on to his sushi repertoire for this new venture, and though the results are largely respectable, the sushi part of the menu feels like an insurance policy: a hedge against diners' possible resistance to the contemporary Korean aspect of the menu.

An entertaining Nara Roll, starring the beloved Korean marinated bulgogi beef wrapped up sushi-style with pickled radish, carrot and omelet, needed only a more pronounced lift of acid to come fully to life. Like a number of dishes at Nara, it's a good idea that's not quite there yet.

I wanted to love a flaky little Bulgogi Pot Pie, but its wan beef filling had only a few chunks of radish to give it a Korean spin. I missed the vigor of classic bulgogi preparations.

House-made Korean rice cakes, smooth little cylinders piled in a ziggurat and crowned with shreddy oxtail, might have been splendid had their chojang sauce - made from the popular Korean sweet red chile paste - contained more rice vinegar to counter the overwhelming sugar content.

A play on soup dumplings was gorgeous to look at, the scalloped noodle caps cradling a central pocket of pork topped by melting dashi gelée. But I wanted a rounder, fuller burst of flavor from the Duroc pork in the filling.

And if only the pork-belly cracklings on top of that hot-stone-bowl bibimbap had not inhabited some vague middle ground between crisp and chewy, the rice dish they adorned would have had some swagger. As it was, the sweet chojang paste that made the bottom layer of rice caramelize to a glassy finish where it met the hot stone bowl so dominated the flavor profile that I longed for a pop of acid to focus the flavors.

A lovely crown arrangement of roasted purple and green cauliflowers with rosy watermelon radish gave me a similar pang. Its sauce of "chogurt" (yogurt tinted with chojang sweet chile paste) just wasn't enough to focus the dish and make it seem special, or persuasively Korean.

Sometimes a dish will fail utterly. A cold dish of transparent sweet-potato noodles clumped together and gained little from its advertised "mushroom ragu." The sautéed fennel was a nice touch, but all the sautéed multicolored bell peppers involved seemed to have wandered in from another universe. (One where mixed grilled vegetables of the day run free.)

A sashimi plate of octopus usuzukuri featured rubbery octopi that were (perhaps mercifully) subjugated by sweet red chile paste, so that its Meyer lemon and cucumber components went for naught. O-toro, the voluptuous prized belly tuna, was glorious as a piece of simple nigiri sushi one night, but fishy-tasting and poised on beady, undercooked rice another. And a so-called "Spicy Butter Crab Roll" was distressingly bland, its snow-crab center unassisted by the advertised togarashi (peppery spice mix) clarified butter or jalapeño.

A piece of hamachi topped with pickled watermelon radish, chive and micro-planed Parmesan shavings turned out so well I wanted to explore the new "Nigiri Sushi with Toppings" section of the menu. Instead of tasting inevitable, as one wants these combinations to turn out, the juxtapositions perplexed. Salmon gained little from beet purée and slivers of candied Meyer lemon; beautifully soft smoked eel gained even less from a dab of persimmon cheesecake.

There are consolations in the form of a decent sake selection, some suitable wines (an elegant Plowbuster Pinot Noir from Oregon and a sprightly Cape Mentelle sauvignon/semillon blend from western Australia both suit this menu particularly well) and a slate of interesting cocktails. I was happy to see a few drinks based on Soju, the Korean rice spirit, including a Pear Soju cocktail sharpened with a little lime. It was like drinking a fresh pear, right down to the slightly fuzzy-tongued sensation imparted by pear skin. Sip to believe.

Service at Nara is personable (sometimes emphatically so) and efficient. The clientele is well dressed and well heeled, to match the room. An evening here feels significant even when some of the food falls short.

But I want more from Chang and from his ambitious venture. Korean food has an increasing hold on the Houston palate in recent years, from the devotees of HMart grocery to the restaurants of Long Point to the menu at mainstream Underbelly. I'm ready for Chang to swing for the fences, to quit hedging his bets, to go big on his vibrant native Korean flavors and textures.